1. Field of the Invention
This invention relates to a particular type of storage buffer apparatus capable of being built-in inbetween machines for processing continuous-strip type of photographic material, and particularly, not only solely suitable for the development of both negatives and positives of photographic materials.
2. Description of the Related Art
Storage buffers are known to be widely used in industrial photographic development plants so as to enable the various processing machines making up the plant, and used to process photographic material in the form of a continuous strip, to synchronously change the speed or rate at which they are processing the photographic strip, for instance in correspondence with starting or shutdown phases or during transient phases of speed variations that inevitably happen to occur among the individual machines making up the plant.
Anyone skilled in the art is furthermore well aware of the fact that such storage buffers should be as compact as possible so as to be able to be conveniently installed even in areas with a limited availability of floor space or, anyway, in restricted areas, while being at the same time fully capable of satisfactorily the largest possible amount of photographic material in as small a space as possible, without the photographic material being exposed to any risk of getting damaged by coming into contact either with itself or dangerous parts of the storage buffer.
Various solutions have therefore been aimed at solving the problem of the availability of efficient, convenient and practical storage buffers. One of the most valid among these solutions is the one described in Italian patent application no. 83455/A/87, which discloses a specific type of storage apparatus for material in the form of a continuous strip, in particular photographic material, equipped with rows of rollers having their rotary axes inclined along the horizontal direction, as well as lower carriages that keep the strip material tensioned due to their own weight.
Such a solution, however, while improving the efficacy of previously developed solutions, still has some drawbacks which become increasingly apparent as operational needs become more exacting. These drawbacks can be summarized as follows:
1) Inertia of the continuous strip
In correspondence of sharp or abrupt accelerations or decelerations in the speed at which the continuous strip is progressing, temporary "redundancies" of strip between pairs of rollers arranged in series occur, which cause the strip to bulge correspondingly so that, when said "redundancies" are then recovered, the same strip undergoes severe jerks that can prove harmful for its integrity.
2) Contact of material
Furthermore, the above-described bulging effect can cause a length of moving strip to collide with an adjacent length of strip moving in the opposite direction, and this would inevitably cause the photographic material to become damaged in a more or less serious manner.
3) Compactness
The particular structural arrangement of the storage buffer illustrated in the aforementioned patent specification compels the continuous strip into being bent around itself when it passes on from a roller to the next one. However, such a twist of the strip cannot exceed a determined angle per unit of length, since the resulting excessive torsion would otherwise damage or distort the strip. In order to prevent this from occurring, the need arises to increase the smallest allowable distance between the rollers. While this is fully feasible, it nevertheless means that said smallest allowable distance automatically determines a minimum storage volume which cannot be used as a dynamic storage space, i.e. one that can be varied according to actual needs or requirements, and which does not perform any useful function as far as the primary actual purpose in using a storage buffer is concerned, i.e. the ability of automatically adapting its capacity to the varying requirements.
However, such a "minimum storage volume" although not performing any practical function, certainly takes up a lot of space and this therefore results in a poorer overall utilization of the space taken up by the storage buffer in its entirety.
4) Accessibility
A further drawback that can be found in connection with known state-of-art equipment lies in that, if the need arises to intervene for any reason whatsoever, access to the strip can only be gained from at least two opposite sides. This of course requires that such equipment not be installed against a wall but at a certain distance therefrom. As a consequence, this requirement to be complied with when installing the equipment makes these products de facto still bulkier and more space-demanding than is actually created by their own volume, thereby resulting in a still poorer coefficient of space utilization per unit of strip that can be stored dynamically.
5) Interchangeability of access
Storage buffers are currently configured such that the continuous strip enters and exists from two specific sides of the equipment, which are usually opposite to each other and are not reversible, i.e. interchangeable. This non-interchangeability of the inlet and exit sides of the equipment lowers the operability thereof, since it makes its integration with the other processing machines more rigid from both a logistic and a functional standpoint.